Repair of macular pucker or epiretinal membrane (ERM) is accomplished through vitreoretinal surgery. Using microsurgical instruments, a procedure known as vitrectomy or removal of vitreous gel from the posterior chamber of the eye is performed. Specialized microsurgical instruments are then used to gently peel and remove the scar tissue from the surface of the retina, relieving the traction and reducing the distortion to the retinal surface. The membrane peel involves identifying the outer edge of the membrane and creating a dissection plane with the use of blunt-tipped pic, bent needle, or diamond dusted silicone cannula. The epiretinal membrane may be gently lifted off the retinal surface with the use of a pic or fine forceps. This procedure is relatively straight forward if the edge of the epiretinal membrane is visible.
When the edge is difficult to identify the surgeon can create a slit on the thickest part of the epiretinal membrane with a straight microvitreoretinal blade and using the opening produced by this slit as an edge to begin peeling of the epiretinal membrane from the retina. The peeling is performed moving the forceps in a circular motion. Petechial hemorrhage along the internal retinal surface may be seen as the membrane is peeled off the retina. Significant bleeding may occur when an underlying vessel is damaged as a strongly adherent epiretinal membrane is peeled from the retina. Postoperative complications include cystoid macular edema (CME), retinal phototoxicity, endophthalmitis, subretinal neovascularization, and recurrent epiretinal membrane.
An alternative approach that has gained favor since the introduction of 25-gauge (25 g) instrumentation is direct peeling of the internal limiting membrane of the retina, which may be referred to as the internal limiting membrane (ILM) peel. The ILM is innermost surface of the retina and is comprised of a thin lamina. In an ILM PEEL, an edge in the ILM is created with a sharp microvitreoretinal blade and an ILM maculorhexis performed with fine forceps, peeling away both the ILM and the overlying adherent ERM.
Removal of epiretinal membrane from the retina by manual peeling is technically demanding and difficult. The retina is between 160 microns and 240 microns thick and is generally transparent. The epiretinal membrane that is grown on the retinal surface is thinner than the retina typically 10-30 microns thick as measured by optical coherence tomography (OCT) and is often friable. This anatomical relationship results in extremely minute tolerances in manual attempt to engage the membrane. The application of too much pressure or misalignment of the position of the tip of the peeling instrument may result in a vision threatening injury that can result from damaging a portion of the retina, such as a region of the fovea.